Conventionally, a sheet article such as a document or a photo is usually covered with a protective film for protection because such a sheet article is readily suffered from damage. Typically, a sheet laminating apparatus (or a laminator) is used for heating and pressing (or laminating) a sheet article between two pieces of protective films in order to achieve the protective purpose. Hereinafter, the configurations of a conventional sheet laminating apparatus will be illustrated with reference to FIG. 1.
FIG. 1 is a schematic cross-sectional view illustrating a conventional sheet laminating apparatus. As shown in FIG. 1, the sheet laminating apparatus 1 comprises a heat-treating mechanism 10, a transmitting and pressing mechanism 11 and a transfer passage 12. The heat-treating mechanism 10 includes a heater 101 and an electrically-heated plate 102. The external surface of the transmitting and pressing mechanism 11 is enclosed by the heater 101. In addition, the heater 101 is separated from the transmitting and pressing mechanism 11 by a gap.
The process for laminating a sheet article (not shown) by using the sheet laminating apparatus 1 will be described as follows. First of all, the sheet article is sandwiched between an upper thermoplastic film and a lower thermoplastic film to form a sandwich structure. Then, the sandwich structure is fed into the transfer passage 12 through an entrance 121. By means of the transmitting and pressing mechanism 11, the sandwich structure is continuously transported through the passage 12. During this stage, the electrically-heated plate 102 of the heat-treating mechanism 10 transforms electricity to heat energy so as to preheat the sandwich structure. The heat energy generated by the electrically-heated plate 102 is uniformly distributed over the heater 101, and radiated through an air gap between the heater 101 and the transmitting and pressing mechanism 11 so as to heat up the transmitting and pressing mechanism 10. The transmitting and pressing mechanism 11 presses against opposite sides of the sandwich structure that is transported through the transfer passage 12, and transmits the heat energy to the sandwich structure so as to soften the thermoplastic films. After being transmitted and pressed by the transmitting and pressing mechanism 11, the sheet article bonds with the softened thermoplastic films to form a laminate structure. Meanwhile, the sheet article is fixed between these two pieces of thermoplastic films.
For most conventional sheet laminating apparatuses utilizing heat energy to laminate sheet articles, a jamming condition is commonly found. In a case that the sheet article is adhered to the transmitting and pressing mechanism 11 during the process of transmitting and pressing the sandwich structure, or in another case that the thermoplastic films become too soft due to the elevated temperature, the possibility of causing the jamming condition in the transfer passage 12 is largely increased. If the sheet article is jammed in the transfer passage 12, the user may generally pull out the jammed sheet article by exerting a pulling force on the sheet article. If the problem of getting jammed is very serious, however, the pulling force is usually insufficient to pull out the jammed sheet article. Under this circumstance, the sheet laminating apparatus 1 may have a breakdown.